Conventional data transactions between a source and a host, i.e. a recipient, may be a unicast transmission where the source sends a data packet to each host or a multicast transmission where the source sends a single data packet or stream of information to a group of hosts. The group of hosts is a multicast group formed of arbitrary recipients that express an interest in receiving the data transmitted by the source. In the multicast transmission, the data packet may be replicated using network devices so that each host in the group gets a copy of the transmission. Accordingly, communication traffic may be reduced using the multicast transmission technology. Exemplary multicast transmissions may include webinars, video/audio conferences, internet radio, internet television, networked games, etc.
In conventional multicast transmissions, the hosts indicate their interest in the data transmitted by the source by sending an Internet Group Management Protocol (IGMP) report to one or more multicast-enabled routers in the network. The routers create a multicast distribution tree via Protocol Independent Multicast (PIM) for delivering the data from the source to the hosts.
The network supporting the multicast traffic may include one or more network devices, such as layer-2 switches. The hosts and routers are exchanging data packets. In a conventional IP multicast, the layer-2 switches optimize multicast data forwarding through a mechanism called IGMP snooping. The layer-2 switches look into, i.e. snoop, the IGMP report to determine the hosts that are interested in the data packet. The layer-2 switches determine the ports that the interested hosts are connected to and forward the multicast traffic to the determined ports.